Dermatofibrosarcoma Protuberans – 4 Interesting Facts
- Dermatofibrosarcoma protuberans (DFSP) is a low- to intermediate-grade sarcoma that usually produces damage by local extension into normal structures. In about 5% to 10% of cases, a DFSP contains a fibrosarcomatous element. This subset of DFSP with fibrosarcomatous change often behaves in a more aggressive fashion. About 5% of all DFSPs will produce metastatic disease, with the lungs and lymph nodes most often involved.
- The most common location for DFSP is the trunk, but it may also occur on the arms, legs, or head and neck.
- The diagnosis may be established by performing a large, deep punch biopsy (6 or 8 mm) or an incisional or excisional biopsy. A shave biopsy should not be performed if DFSP is a serious diagnostic consideration.
- Complete surgical extirpation of the tumor with 2- to 4-cm margins is the most commonly used treatment.
Etiology and Risk Factors
- Dermatofibrosarcoma protuberans (DFSP), although a rare neoplasm overall, is the most common cutaneous sarcoma. The incidence is estimated to be about 4.2 cases/million persons per year. The cause of the neoplasm is debated, but the tumor is likely derived from CD34+ dendrocytes normally found in the dermis. Most DFSPs possess a reciprocal translocation of chromosomes 17 and 22 or, less often, a supernumerary ring chromosome comprised of portions of chromosomes 17 and 22.
- DFSP is most common in 20- to 59-year-olds but can even be present at birth or in older adults.
Workup
Physical Examination
- The most common location for dermatofibrosarcoma protuberans (DFSP) is the trunk, but it may also occur on the arms, legs, or head and neck.
- Typically, DFSP presents as a slow-growing exophytic papule that enlarges to produce additional papules and nodules of various sizes, which protrude above the skin surface. However, atrophic plaque-like forms, without a protuberant appearance, are not uncommon.
- DFSP is typically skin-colored, but it can be red, pink, or white (the latter in atrophic areas).
- DFSP is usually asymptomatic, but 10% to 20% of patients with a DFSP report local pain or discomfort.
- Bednar tumor is an uncommon type of DFSP that is pigmented because of admixed melanocytes.
Diagnostic Procedures
- The diagnosis may be established by performing a large, deep punch biopsy (6 or 8 mm) or an incisional or excisional biopsy. A shave biopsy should not be performed if DFSP is a serious diagnostic consideration.
- Nearly all DFSPs mark with a CD34 immunohistochemical stain, which is an important part of the overall histologic evaluation.
Differential Diagnosis
- The differential diagnosis includes a dermatofibroma, hypertrophic scar, keloid, or any other soft-tissue tumor. Often, the diagnosis of a DFSP is suspected because of the clinical history of a slow-growing tumor, with a protuberant papulonodular quality.
Treatment
Drug Therapy
- For patients with unresectable tumors or with metastatic disease, imatinib is the treatment of choice.
Treatment Procedures
- Complete surgical extirpation of the tumor with 2- to 4-cm margins is the most commonly used treatment.
- Select cases may require adjuvant radiation therapy.
- Mohs surgery has also been used, with some degree of success.
References
1.Han A, et al. Neoadjuvant imatinib therapy for dermatofibrosarcoma protuberans. Archives of Dermatology. 2009;145(7):792-6.
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2.Kallini J R, et al. Dermatofibrosarcoma protuberans: is mohs surgery truly superior? And the success of tyrosine kinase inhibitors. Journal of Drugs in Dermatology. 2014;13(12):1474-7.
